The development of new endoscopic applications of ultrasound imaging is critically dependent on the availability of efficient broadband transducers with areas of 2 mm2 or less. The material properties of PZT ceramics for operation in the thickness mode at frequencies as high as 80 MHz are reported. Each of the ceramics tested showed a reduction in k, with increasing frequency. In a fine grained PZT, values of k, as high as 0.44 were measured at 80 MHz. The effects of grain size were also

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... in the measurement of frequency dependent mechanical losses. Experimental and theoretical analysis of I mm2 45-kIHz PZT transducer verified the validity of the properties measurements and demonstrated excellent insertion loss and bandwidth characteristics. The minimum insertion loss of -17.5 dB is in good agreement with theory and is a marked improvement over the performance of polymer devices. Details on the fabrication and testing of high frequency ceramic transducers are described.